Urticaria can be acute, chronic or physical. But when you first get urticaria, you cannot tell how long they will last, and so you cannot tell if you have acute or chronic lesions.
Although all type of urticarial lesions look similar, they often have different triggers. Learning what trigger your urticaria can help you to avoid trigger.

Acute urticaria:

• Hives will not last beyond a few days or will last for a maximum of 6 weeks.
• Triggers of acute hives include infections, drugs, insect stings (bees, wasp,ants), food allergies and physical contact with certain agents.
• Food associated urticaria appears within 30 minutes of eating the food and the foods most likely to cause it include milk, eggs, peanuts, other nuts, soy, wheat, fish and shellfish. Physical contact with plants, raw fruits, vegetable and latex can cause urticaria in certain individuals.

Chronic uricaria:

• Hives occurs almost daily and last longer than 6 weeks, sometimes for years. These hives come and go and can interfere with sleep, work or school.
• In most cases of chronic hives, the cause is unknown. Problem in the immune system may play a role. It can be a sign of medical or autoimmune condition, including thyroid or liver diseases, chronic infection or lupus.
• Food additives like colorants, preservatives and essence and NSAIDs are important trigger of both acute or chronic urticaria.

Physical urticaria:

• Hives can be triggered by physical factor like exposure to cold, changes in temperature or sweating, vibration, pressure, exercise, sunlight or water.
• Dermatographism is a type of physical urticaria in which red, raised lines develop if the skin is stroked firmly or scratched. Physical form of hives tend to be long lasting.